Sub-Arctic no more: Short- and long-term global-scale prospects for snow crab (Chionoecetes opilio) under global warming

Snow crab is a sea-ice associated species that supports several economically important fisheries in northern latitudes. During the past decade considerable stock range changes have occurred, characterized by a general shift from sub-Arctic ecosystems into the Arctic. We developed predictive models for short-term biomass trajectories and long-term habitat potential under a changing climate. Sea ice extent and the Arctic Oscillation were important variables in the short-term models. Future sea ice extent was used as an analog for long-term habitat potential and was predicted as a function of projected atmospheric carbon dioxide concentrations and the Arctic Oscillation. Our results show that global scale snow crab habitat and biomass are currently at or near historically measured highs. Similar overall habitat potential to historic and current levels is expected to continue out to 2100 under best case CO 2 scenarios but declines below historic levels are projected to begin after about 2050 under worst cast CO 2 scenarios. In the short-term, most historical stock ranges are expected to maintain productive fisheries while new habitats open. In the long-term, under all CO 2 scenarios, we project a shift in habitats from historic ranges into new frontiers as sea ice recedes. Future population trajectories depend upon the ability of snow crab to track habitat shifts and we discuss possible forthcoming changes in context of potential socioeconomic outcomes.